Mount Prospect, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

742
FXUS63 KLOT 130710
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
210 AM CDT Sat Jun 13 2026

.KEY MESSAGES...

- Scattered thunderstorms late this afternoon through early
  Sunday morning. A few storms could be strong to severe.

- Possible dangerous swimming conditions at Indiana Lake
  Michigan beaches Sunday.

- Cooler temperatures early next week with precipitation
  chances returning midweek.

&&

.DISCUSSION...
Issued at 210 AM CDT Sat Jun 13 2026

Overall confidence remains low for convective/precip trends
later today into tonight. This morning is expected to be dry
areawide and then there will be a low chance (20%) for showers
and thunderstorms mainly across the southern cwa this afternoon.
As a cold front approaches the area this evening, that seems to
be the best time window for thunderstorms, late afternoon across
far northwest IL and then for areas along and north of I-80
during the evening. Showers may increase in coverage later this
evening and into the overnight hours with perhaps just isolated
thunderstorms at that time. The potential for a few storms to
become strong to severe remains with the best timing in the late
afternoon into the evening hours. Heavy rain and localized
flooding would also be possible with any stronger storms. End
time of the precipitation is also somewhat uncertain, ending
from northwest to southeast Sunday morning with some shower
activity still possible along/southeast of I-57 after daybreak
Sunday morning.

With the expectation that much of the daylight hours today could
be dry with at least some sunshine through early afternoon,
high temps may make a run at upper 80s for many areas today and
nudged temps up some. Southwest winds will also quickly
increase after sunrise with gusts into the 30 mph range possible
today.

A cold front will move across the area early Sunday morning,
shifting winds northerly and bringing in much cooler air. High
temps on Sunday may struggle to reach the lower 70s and likely
be dependent on how long cloud cover persists on Sunday with
some sunshine expected by afternoon. North/northwest winds may
gust as high as 30 mph on Sunday and these stronger winds will
allow waves to build across southern Lake Michigan, leading to
dangerous swimming conditions at Lake Michigan beaches in
Indiana and possibly some of the Illinois beaches depending on
the exact wind direction.

No significant changes in the models for the pattern next week.
An upper trough is expected to move across the Great Lakes
region midweek bringing increasing precipitation chances by
Wednesday and Wednesday night ahead of another cold front which
may bring another short burst of cooler air for the end of the
week. cms

&&

.AVIATION /06Z TAFS THROUGH 12Z SUNDAY/...
Issued at 1234 AM CDT Sat Jun 13 2026

Forecast concerns include...

Chance of thunderstorms late this afternoon into this evening.
Gusty southwest winds today and gusty northwest winds Sunday.
Wind shift to north/northwest early Sunday morning.
Possible mvfr cigs tonight into Sunday morning.

Southwest winds under 10kt early this morning will increase
quickly after sunrise with speeds into the 15kt range and gusts
into the mid 20kt range through late afternoon. Speeds and gusts
are expected to slowly diminish in the early evening, turn more
westerly by late evening and then shift to the north/northwest
as a cold front moves across the area early Sunday morning.
Gusts into the 20kt range will be possible in the predawn hours
Sunday morning.

There remains quite a bit of uncertainty for shower and
thunderstorm coverage and timing later this afternoon into
tonight. The highest coverage of thunderstorms may remain south
of the terminals in the vicinity of an area of low pressure that
will move across central IL this evening. Isolated showers or
thunderstorms are possible this afternoon and if they do
develop, also possibly south of the terminals. The best chance
for thunderstorms appears to be from late afternoon through mid
evening for all of the terminals, ahead of the cold front. There
may be isolated thunderstorms and scattered showers that linger
into the early morning Sunday. Current prob thunder and then
vicinity shower mention has the current expectations handled
well and confidence is too low to make any changes with this
forecast.

Mvfr cigs will be possible tonight into Sunday morning and will
likely be dependent on the precipitation coverage. Have included
sct mvfr mention with this forecast with confidence too low for
prevailing mvfr cigs at this time. cms

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.

&&

$$

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